Magnum manifolds on 67 Dart?
I run them on my Valiant. When I first mocked up my motor in my Valiant, I used a set of j heads on a 68 318 block, and I could not get them to fit, so I just planned on using the stock manifolds for the car. Then when I put the 65 273 with magnum heads in, I thought I better try it again, as maybe I was tired when I first tried it a year earlier, it went right in, and cleared nicely. they are rear dump, so if you run a clutch, it will hit the z bar, and I spose an auto column linkage would hit too. I am running a hydro release bearing so I was able to run the manifolds with no worry.
Mine are off of a 96, and they have 2 inch outlets, I planned on running two inch into a single three anyways, so no need for a bigger outlet manifold.
If you are running the studs on the ends of the head, I am pretty sure you wouldnt be able to get them on while the engine is in the car, as its pretty tight.